To investigate the utility of multiparametric magnetic resonance imaging (mpMRI) in the reassessment and monitoring of patients on active surveillance (AS) for Grade Group (GG) 1 prostate cancer (PCa).
Patients and Methods
We identified, from our prospectively maintained IRB‐approved database, 181 consecutive men enrolled on AS for GG 1 PCa who underwent at least one surveillance mpMRI followed by MRI/prostate biopsy (PBx). A subset analysis was performed among 68 patients who underwent serial (at least two) mpMRI/PBx during AS. Pathological progression (PP) was defined as upgrade to GG ≥ 2 on follow up biopsy. Statistically significant if p<0.05.
Baseline MRI was performed in 34 (19%) patients. In a median follow up of 2.2 years for the overall cohort, the PP was 12% (6/49) for PIRADS 1‐2 and 37% (48/129) for PIRADS≥ 3. The 2‐year PP‐free survival was 84%. Surveillance PSA density (p<0.001) and surveillance PIRADS ≥ 3 (p=0.002) were independent predictors for PP on reassessment MRI/PBx. In serial MRI cohort, the 2‐year PP‐free survival was 95% for no MRI‐progression vs 85% for MRI‐progression group (p=0.02). MRI progression was significantly higher in PP (62%) than in no‐PP (31%) group (p=0.04). If serial MRI is used for PCa surveillance and biopsy is triggered based only on MRI progression, 63% of PBx might be postponed by the cost of missing 12% of GG≥2 PCa in those with stable MRI. Conversely, this strategy would miss 38% of those with upgrading to GG≥2 PCa on biopsy. Stable serial mpMRI correlates with no reclassification to GG ≥ 3 PCa during AS.
PIRADS ≥ 3 on surveillance mpMRI is associated with increased risk of PCa reclassification. Surveillance biopsy based only on MRI progression may avoid large number of biopsies with the cost of missing many PCa reclassification.